Electronic smoking article

ABSTRACT

An electronic smoking article includes a reservoir including a liquid aerosol formulation, a heater operable to at least partially volatilize the liquid aerosol formulation and form an aerosol, and a filter segment formed of polylactic acid fibers or a crimped polylactic acid film. The filter segment includes at least one additive and is positioned downstream of the heater.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119(e) to U.S. provisional Application No. 61/858,343, filed on Jul. 25, 2013, the entire content of which is incorporated herein by reference thereto.

WORKING ENVIRONMENT

Many of the embodiments disclosed herein include electronic smoking articles operable to deliver liquid from a liquid supply source to a heater. The heater volatilizes a liquid to form an aerosol.

SUMMARY OF SELECTED FEATURES

An electronic smoking article, such as an electronic smoking article, operable to produce an aerosol includes a liquid aerosol formulation, a heater operable to at least partially volatilize the liquid aerosol formulation and form an aerosol, and a filter segment formed of polylactic acid fibers or a crimped polylactic acid film. The filter segment includes at least one additive and is positioned downstream of the heater. The filter segment is operable to elute the at least one additive into the aerosol as the aerosol passes through the filter segment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an electronic smoking article constructed according to the teachings herein.

FIG. 2 is a cross-sectional view of an electronic smoking article according to a first embodiment.

FIG. 3 is a cross-sectional view of another embodiment of an electronic smoking article according to a second embodiment.

FIG. 4 is a cross-sectional view of an electronic smoking article according to a third embodiment.

FIG. 5 is a perspective view of a filter segment as described herein.

FIG. 6 is a cross-sectional view of an electronic smoking article according to a fourth embodiment including the filter segment of FIG. 5.

FIG. 7 is a perspective view of a detachable filter segment.

FIG. 8 is a cross-sectional view of an electronic smoking article according to a fifth embodiment including the detachable filter segment of FIG. 7.

DETAILED DESCRIPTION

An electronic smoking article includes a liquid supply (reservoir) containing a liquid aerosol formulation. The liquid aerosol formulation is delivered to a heater where the liquid aerosol formulation is heated, volatilized, and forms an aerosol. As used herein, the term “electronic smoking article” is inclusive of all types of electronic smoking articles, regardless of form, size or shape, including electronic cigarettes, electronic cigars, electronic pipes, electronic hookahs and the like. The liquid aerosol formulation can include nicotine or be nicotine free. Moreover, the liquid aerosol formulation can include tobacco flavors or instead, or in combination include other suitable flavors.

Preferably, the aerosol passes through a filter segment formed of a low efficiency filter material, such as polylactic acid (PLA) in the form of a rod. Preferably, the filter includes PLA fibers that are arranged such that the fibers are substantially parallel and have a plurality of passages therebetween and/or a crimped PLA film having hollow channels extending parallel to the direction of the aerosol flow so as to allow for minimal resistance to draw and minimal aerosol filtration. Accordingly, as the aerosol passes through the PLA filter segment, additives, such as flavors and/or volatile acids, are eluted into the aerosol so as to alter the sensory experience of the aerosol. Moreover, the composition and arrangement of the fibers in the filter segment results in minimal resistance to aerosol flow therethrough and/or minimal filtration of the aerosol. The type of additives, location of the additives in the filter, composition of the additives, and the like can be altered to provide controlled release of additives into the aerosol as it passes through the filter segment.

Preferably, as shown in FIGS. 2, 3, 4, 6, and 8, the electronic smoking article 60 comprises a replaceable cartridge (or first section) 70 and a reusable fixture (or second section) 72, which are coupled together at a threaded joint 74 or by other convenience such as a snug-fit, snap-fit, detent, clamp and/or clasp.

As shown in FIG. 3, the first section 70 can house a mouth-end insert 20, the filter segment 600, a capillary aerosol generator including a capillary (capillary tube) 18, a heater 19 to heat at least a portion of the capillary 18, a reservoir 14 and optionally a valve 40. Alternatively, as shown in FIG. 4, the first section 70 can house a mouth end insert 20, the filter segment 600, a heater 319, a flexible, filamentary wick 328 and a reservoir 314 as discussed in further detail below.

The second section 72 can house a power supply 12 (shown in FIGS. 2, 3 and 4), control circuitry 11, and optionally a puff sensor 16 (shown in FIGS. 3 and 4). The threaded portion 74 of the second section 72 can be connected to a battery charger when not connected to the first section 70 for use so as to charge the battery.

As shown in FIG. 2, the electronic smoking article 60 can also include a middle section (third section) 73, which can house the reservoir 14, heater 19 and valve 40. The middle section 73 can be adapted to be fitted with a threaded joint 74′ at an upstream end of the first section 70 and a threaded joint 74 at a downstream end of the second section 72. In this embodiment, the first section 70 houses the mouth-end insert 20 and the filter segment 600, while the second section 72 houses the power supply 12 and control circuitry.

Preferably, the first section 70, the second section 72 and the optional third section 73 include an outer cylindrical housing 22 extending in a longitudinal direction along the length of the electronic smoking article 60. In one embodiment, the middle section 73 is disposable and the first section 70 and/or second section 72 are reusable. In another embodiment, the first section 70 can also be replaceable so as to avoid the need for cleaning the capillary 18 and/or heater 19. The sections 70, 72, 73 can be attached by threaded connections whereby the middle section 73 can be replaced when the reservoir 14 is used up.

In another embodiment, the housing 22 may comprise a single, unitary tube, without any threaded connections.

As shown in FIG. 2, the outer cylindrical housing 22 can include a cutout or depression 102 which allows a smoker (vaporer) to manually apply pressure to the reservoir 14. Preferably, the outer cylindrical housing 22 is flexible and/or compressible along the length thereof and fully or partially covers the reservoir 14. The cutout or depression 102 can extend partially about the circumference of the outer cylindrical housing 22. The reservoir 14 is compressible such that when pressure is applied to the reservoir, liquid is pumped from the reservoir 14 to the capillary 18. A pressure activated switch 44 can be positioned beneath the reservoir 14. When pressure is applied to the reservoir 14 to pump liquid, the switch is also pressed and a heater 19 is activated. The heater 19 can be a portion of the capillary 18.

In the embodiment of FIG. 2, the reservoir 14 is a tubular, elongate body formed of an elastomeric material so as to be flexible and/or compressible when squeezed. Preferably, the elastomeric material can be selected from the group consisting of silicone, plastic, rubber, latex, and combinations thereof.

Preferably, the compressible reservoir 14 has an outlet 16 which is in fluid communication with a capillary 18 so that when squeezed, the reservoir 14 can deliver a volume of liquid material to the capillary 18. Simultaneous to delivering liquid to the capillary, the power supply 12 is activated upon application of manual pressure to the pressure switch and the capillary 18 is heated to form a heated section wherein the liquid material is volatilized. Upon discharge from the heated capillary 18, the volatilized material expands, mixes with air and forms an aerosol.

Preferably, the reservoir 14 extends longitudinally within the outer cylindrical housing 22 of the first section 70 (shown in FIGS. 3 and 4) or the middle section 73 (shown in FIG. 2). The reservoir 14 comprises a liquid aerosol formulation which is volatilized when heated and forms an aerosol when discharged from the capillary 18.

In the preferred embodiments of FIGS. 2 and 3, the capillary 18 includes an inlet end 62 in fluid communication with the outlet 16 of the reservoir 14, and an outlet end 63 operable to expel volatilized liquid material from the capillary 18. In a preferred embodiment, as shown in FIGS. 2 and 3, the reservoir 14 may include a valve 40.

As shown in FIG. 2, the valve 40 can be a check valve that is operable to maintain the liquid material within the reservoir, but opens when the reservoir 14 is squeezed and pressure is applied. Preferably, the check valve 40 opens when a critical, minimum pressure is reached so as to avoid inadvertent dispensing of liquid material from the reservoir 14 or activating the heater 19. Once pressure upon the reservoir 14 is relieved, the valve 40 closes. The heated capillary 18 discharges liquid remaining downstream of the valve 40.

As shown in FIG. 3, in other embodiments, the valve 40 can be a two-way valve and the reservoir 14 can be pressurized. For example, the reservoir 14 can be pressurized using a pressurization arrangement 405 which applies constant pressure to the reservoir 14. For example, pressure can be applied to the reservoir 14 using an internal or external spring and plate arrangement which constantly applies pressure to the reservoir 14. Alternatively, the reservoir 14 can be compressible and positioned between two plates that are connected by springs or the reservoir 14 could be compressible and positioned between the outer housing and a plate that are connected by a spring so that the plate applies pressure to the reservoir 14.

Preferably, the capillary 18 of FIGS. 2 and 3 has an internal diameter of 0.01 to 10 mm, preferably 0.05 to 1 mm, and more preferably 0.05 to 0.4 mm. Also preferably, the capillary 18 may have a length of about 5 mm to about 72 mm, more preferably about 10 mm to about 60 mm or about 20 mm to about 50 mm. In one embodiment, the capillary 18 is substantially straight. In other embodiments, the capillary 18 is coiled and/or includes one or more bends therein to conserve space and/or accommodate a long capillary.

In these embodiments, the capillary 18 is formed of a conductive material, and thus acts as its own heater 19 by passing current through the capillary. The capillary 18 may be any electrically conductive material capable of being resistively heated, while retaining the necessary structural integrity at the operating temperatures experienced by the capillary 18, and which is non-reactive with the liquid material. Suitable materials for forming the capillary 18 are selected from the group consisting of stainless steel, copper, copper alloys, porous ceramic materials coated with film resistive material, Inconel® available from Special Metals Corporation, which is a nickel-chromium alloy, nichrome, which is also a nickel-chromium alloy, and combinations thereof.

Alternatively, the capillary 18 may be a non-metallic tube such as, for example, a glass tube having a conductive material capable of being resistively heated, such as, for example, stainless steel, nichrome or platinum wire, arranged there along.

Preferably, at least two electrical leads 26 are bonded to a metallic capillary 18 by brazing or crimping. Preferably, one electrical lead 26 is attached to a first, upstream portion 101 of the capillary 18 and a second electrical lead 26 is attached to a downstream, end portion 104 of the capillary 18, as shown in FIGS. 2 and 3.

As noted above, the filter segment 600 can also be used in an electronic smoking article including a heater 319 and a filamentary wick 328 as shown in FIG. 4. The first section 70 includes an outer tube (or casing) 22 extending in a longitudinal direction and an inner tube (or chimney) 362 coaxially positioned within the outer tube 322. Preferably, a nose portion 361 of an upstream gasket (or seal) 320 is fitted into an upstream end portion 365 of the inner tube 362, while at the same time, an outer perimeter 367 of the gasket 320 provides a liquid-tight seal with an interior surface 397 of the outer casing 22. The upstream gasket 320 also includes a central, longitudinal air passage 315, which opens into an interior of the inner tube 362 that defines a central channel 321. A transverse channel 333 at an upstream portion of the gasket 320 intersects and communicates with the central channel 315 of the gasket 320. This channel 333 assures communication between the central channel 315 and a space 335 defined between the gasket 320 and a threaded connection 74.

Preferably, a nose portion 393 of a downstream gasket 310 is fitted into a downstream end portion 381 of the inner tube 362. An outer perimeter 382 of the gasket 310 provides a substantially liquid-tight seal with an interior surface 397 of the outer casing 22. The downstream gasket 310 includes a central channel 384 disposed between the central passage 321 of the inner tube 362 and the mouth end insert 20.

In this embodiment, the reservoir 314 is contained in an annulus between an inner tube 362 and an outer casing 22 and between the upstream gasket 320 and the downstream gasket 310. Thus, the reservoir 314 at least partially surrounds the central air passage 321. The reservoir 314 comprises a liquid material and optionally a liquid storage medium (not shown) operable to store the liquid material therein.

The inner tube 362 has a central air passage 321 extending therethrough which houses the heater 319. The heater 319 is in contact with the filamentary wick 328, which preferably extends between opposing sections of the reservoir 314 so as to deliver the liquid aerosol formulation from the reservoir to the heater 319.

Preferably, the electronic smoking article 60 of each embodiment described herein also includes at least one air inlet 440. As shown in FIG. 4, the at least one air inlet 440 can be located upstream of the heater 319.

In the embodiments shown in FIGS. 2 and 3, the at least one air inlet 440 is arranged downstream of the capillary 18 so as to minimize drawing air along the capillary and thereby avoid cooling of the capillary 18 during heating cycles.

The power supply 12 of each embodiment can include a battery arranged in the electronic smoking article 60. The power supply 12 is operable to apply voltage across the heater 19 associated with the capillary 18, as shown in FIGS. 2 and 3, or the heater 319 associated with the filamentary wick 328, as shown in FIG. 4. Thus, the heater 19, 319 volatilizes liquid material according to a power cycle of either a predetermined time period, such as a 2 to 10 second period.

The battery can be a Lithium-ion battery or one of its variants, for example a Lithium-ion polymer battery. Alternatively, the battery may be a Nickel-metal hydride battery, a Nickel cadmium battery, a Lithium-manganese battery, a Lithium-cobalt battery or a fuel cell. In that case, preferably, the electronic smoking article 60 is smokable by a smoker until the energy in the power supply is depleted. Alternatively, the power supply 12 may be rechargeable and include circuitry allowing the battery to be chargeable by an external charging device. The control circuitry 11 can be programmable and can include an application specific integrated circuit (ASIC). In other embodiments, the control circuitry 11 can include a microprocessor programmed to carry out functions such as heating the capillaries and/or operating the valves.

Preferably, the electronic smoking article 60 of each embodiment also includes control circuitry which can be on a printed circuit board 11 (shown in FIGS. 2, 3 and 4). The control circuitry 11 can also include a heater activation light 27 (shown in FIGS. 2, 3 and 4) that is operable to glow when the heater 19, 319 is activated.

As shown in FIGS. 2, 3, 4, 6, 8 and 9 the electronic smoking article 60 includes the filter segment 600 at a location downstream of the heater 19, 319. In one embodiment, the filter segment 600 is constructed from polylactic acid fibers. The polylactic acid fibers are arranged parallel to one another so that the aerosol flows through channels between the fibers with minimal resistance. In another embodiment, the filter segment 600 is constructed from a crimped polylactic acid film having hollow channels extending parallel to the direction of the aerosol flow so as to allow for minimal resistance to draw and minimal filtration of the aerosol. Thus, the filter segment 600 is an ultra low efficiency filter that is designed primarily to deliver flavors and other additives, such as volatile acids, to the aerosol rather than to filter particles and/or aerosol constituents therefrom. In other embodiments, the filter segment 600 could be formed of other films or planar structures made from extrusion of thermoplastic polymers, paper or stiff nonwoven structures that can be crimped so as to effectively result in filtering segments having hollow channels therein.

Preferably, the filter segment 600 is about 2 mm to about 30 mm in length. More preferably, the filter segment 600 is about 5 mm to about 25 mm in length (e.g., about 10 to about 20 nun or about 12 to about 18 mm). In addition, the outer diameter of the filter segment 600 is about the same or less than the diameter of the electronic smoking article 60.

In the preferred embodiment, the filter segment 600 minimizes resistance to draw (RTD) in the electronic smoking article 60 and can be included inside the first section 70 during manufacture or can be a detachable filter segment, as shown in FIGS. 7 and 8, for addition to the electronic smoking article 60 if desired by the smoker.

As shown in FIGS. 7 and 8, a sleeve portion 604 designed to fit around the outer perimeter of the mouth end of the electronic smoking article 60 and around a portion of the filter segment 600 can be used so attach and detach the filter segment 600 from the electronic smoking article 60. The sleeve portion 604 can be sized to friction fit with the filter segment 600 and with a mouth end of the electronic smoking article 60. The sleeve portion 604 can be colored, scented or include indicia thereon.

As shown in FIG. 6, the electronic smoking article 60 can include the filter segment 600 at the mouth end of the electronic smoking article 60, and no additional mouth end insert is included. In other embodiments, as shown in FIG. 4, a mouth end insert 20 can be positioned downstream of the filter segment 600. Alternatively, the mouth end insert 20 can be positioned upstream of the filter segment 600 as shown in FIG. 8.

In a preferred embodiment, additives including flavors, nicotine, volatiles acids, and/or aerosol modifiers can be applied to the filter segment 600 so that additives are eluted into the aerosol as the aerosol passes therethrough. Suitable additives include those disclosed in co-pending patent application Ser. No. 13/755,616, filed Jan. 31, 2013, the entire content of which is incorporated herein in its entirety by reference thereto. Any additives included in the filter segment 600 can also be included in the liquid aerosol formulation. Alternatively, different additives are included in the filter segment 600 and the liquid aerosol formulation.

Preferred additives also include volatile acids. When volatile acids are eluted into the aerosol, the pH of the aerosol of the aerosol is lowered and the volatile acid reacts with vapor phase nicotine to reduce any perceived harshness of the aerosol. In one embodiment, nicotine in the aerosol can react with an acid to form a nicotine salt in the particulate phase of the aerosol.

For example, the additives can be applied as a coating 606 (shown in FIG. 8) on an outer surface of the filter segment 600 or the flavors and/or aerosol modifiers can be impregnated in the filter segment 600. The additives can be microencapsulated with water soluble materials having varying levels of water solubility so as to provide controlled release of the additive over a period of time. Moreover, the additives can be chosen to provide a preferred flavor profile. When the filter segment 606 includes the coating 606 and is impregnated with additives, the coating 606 includes the same additive as that impregnated in the filter segment 600 or different additives. By including an additive-containing coating 606 along with the additives impregnated in the filter segment 600, release of the additives can be staggered during smoking (vaping) and/or multiple additives can be delivered.

As used herein, the term “additive” means any material or component which modifies the characteristics of the electronic smoking article 60 when the electronic smoking article 60 is smoked (vaped). Any appropriate additive material or combination of materials may be contained in the filter segment 600. Such additive materials include flavor materials, aromatic materials, pH modifying agents, volatile acids, chemesthesis agents including cooling agents and warming agents, carbon dioxide formers, commercially available flavor systems, nicotine in liquid, salt or powder form, and other smoke modifiers.

When formed of a crimped PLA film, the filter segment 600 can be coated with additives prior to being crimped. The additives can be liquid or particulate form, and can be added to the filter segment 600 before or after crimping, by impregnation or infusion of the additives facilitated by, for example, spraying. Liquid additives can be held in pleats of a crimped filter segment 600 by capillary forces. The additives may also be combined in solution or mixture with an extrudable polymer, such as PLA, prior to forming the flavored and/or additive laden filter segment 600.

As used herein, the term “flavor material” means any liquid or solid flavor containing material or formulation that can release flavors and/or aromas into the aerosol stream. Suitable flavors or flavorings include, but are not limited to, menthol, mint, such as peppermint and spearmint, chocolate, licorice, citrus and other fruit flavors, gamma octalactone, vanillin, ethyl vanillin, breath freshener flavors, spice flavors such as cinnamon, methyl salicylate, linalool, bergamot oil, geranium oil, lemon oil, ginger oil, and tobacco flavor. Other suitable flavors may include flavor compounds selected from the group consisting of an acid, an alcohol, an ester, an aldehyde, a ketone, a pyrazine, combinations or blends thereof and the like.

The flavor material can be in the form of particles, granules, fibers, capsules, microcapsules, powders, crushed plant material, aromatic barks, seeds, pieces of dried fruits and/or root material, or any other suitable form. For example, the flavor material can include tobacco beads, flavor beads, mentholated flavor beads, flavor capsules and other flavor materials as used in traditional tobacco smoke filters.

Suitable flavor materials can be non-volatile or volatile and can be delivered to the mouth via the condensation of the aerosol in the filter followed by entrapment and/or dissolution of the flavor material in droplets and/or deposition of the droplets to the tongue of the smoker during a puff. The droplets can consist of constituents used to form the aerosol including propylene glycol, glycerin, water and optionally nicotine. The flavor material can be released into the aerosol and/or can be delivered to a smoker's mouth via contact with moisture from the smoker's lips.

The flavor materials can provide a bitter taste. Suitable compounds which provide a bitter taste include, without limitation, caffeine, denatonium benzoate, theobromine, quinine, and naringin.

The flavor materials can provide a sour taste. Suitable compounds which provide a sour taste include, without limitation, citric acid, malic acid, succinic acid and tartaric acid.

The flavor materials can provide a salty taste. Suitable compounds which provide a salty taste include, without limitation, sodium chloride and potassium chloride.

The flavor materials can provide a sweet taste. Suitable compounds which provide a sweet taste include, without limitation, carbohydrates, including sucrose, and high intensity sweeteners, including sucralose and saccharin.

The flavor materials can provide umami and mouth feel. Suitable compounds which provide umami and mouth feel include, without limitation, monosodium glutamate, gamma-glutamyl peptides, such as gamma-glutamycysteine-beta-alanine, (R)-strombine.

The flavorant can be added to the filter segment 600 in an amount ranging from about 0.2% to about 15% by weight (e.g., about 1% to about 12%, about 2% to about 10%, or about 5% to about 8%). The at least one flavorant can be a natural flavorant or an artificial flavorant.

In one embodiment, the additive can be a chemesthesis agent and/or can be chosen to alter the mouthfeel of the aerosol. For example, the additive can be a chemesthesis agent that provides a warm, tingling sensation and/or a cooling sensation. Additives such as capsaicin, piperine, alpha-hydroxy-sanshool, and (8)-gingerole can be included to provide a warm, tingling or burning sensation. Additives including menthol, menthyl lactate, WS-3 (N-Ethyl-p-menthane-3-carboxamide), WS-23 (2-Isopropyl-N,2,3-trimethylbutyramide) and Evercool 180™ can be included to provide a cooling sensation. In addition, the additive can include extracts, such as coffee extract, red pepper extract, ginger extract and peppermint oil.

During smoking, as aerosol travels through the filter segment 600, additives impregnated in and/or coated on the filter segment can be at least partially eluted into the aerosol for delivery to the smoker. The concentration of additives in the filter segment 600 can be varied depending on the desired strength of the flavor and/or additives. In addition, additives entrained within channels of the filter segment 600 can be subjected to physical dislodgement and entrainment in the aerosol flow.

Preferably, the filter segment 600 is located far enough downstream of the heater 19, 319 so as to minimize heat exposure of the additives and substantially prevent degradation thereof. Also preferably, the filter segment 600 is located so that the filter segment 600 and/or additives contained therein are not exposed to temperatures above about 150° C.

In one embodiment, the at least one additive can include at least one volatile acid, such as pyruvic acid. When pyruvic acid or other volatile acids are included in the filter segment, the acid is eluted into the aerosol and lowers the pH thereof. Accordingly, the vapor phase nicotine of the aerosol is also lowered and harsh sensory perceptions are reduced.

Also preferably, the acid is included in the filter segment 600 in an amount sufficient to reduce the pH of the aerosol to a pH ranging from about 4 to about 8, more preferably about 5 to about 7 or about 5.5 to about 6.5.

Preferably, the acid is added to the filter segment 600 in a solution including the acid in an amount ranging from about 0.1% by weight to about 25% by weight (e.g., about 1% to about 20%, about 2% to about 15%, about 3% to about 10% or about 4% to about 8%).

For example, the filter segment 600 can be a PLA filter plug having a length of about 7 mm. The filter plug can be coated with a solution of 20% pyruvic acid in an 80:20 ratio of glycerin to water. The PLA filter plug can be attached to the electronic cigarette to produce an aerosol having a milder and less irritating effect on the throat as compared to electronic cigarettes not including such a filter segment.

In another example, the filter segment 600 can be a PLA filter plug coated with a solution of 20% menthol in a mixture of 50:50 propylene glycol and glycerol to provide an aerosol having a sensation and flavor of menthol.

In yet another example, the filter segment 600 can be a PLA filter plug having a small amount of flavor in a 50:50 propylene glycol and glycerol mixture applied thereto to provide a flavored aerosol.

As shown in FIGS. 2, 3, 4, and 8, the electronic smoking article 60 can further include the mouth-end insert 20 having at least two off-axis, preferably diverging outlets 21. Preferably, as shown in FIGS. 2, 3, and 4, the mouth-end insert is located downstream of the filter segment 600. In other embodiments, as shown in FIG. 8, the filter segment 600 can be downstream of the mouth-end insert 20.

Preferably, the mouth-end insert 20 includes at least two diverging outlets 21. (e.g. 3, 4, 5, or preferably 6 to 8 outlets or more). Preferably, the outlets 21 of the mouth-end insert 20 are located at ends of off-axis passages 23 and are angled outwardly in relation to the longitudinal direction of the electronic smoking article 60 (i.e., divergently). As used herein, the term “off-axis” denotes at an angle to the longitudinal direction of the electronic smoking article.

In a preferred embodiment, the electronic smoking article 60 is about the same size as a conventional smoking article. In some embodiments, the electronic smoking article 60 can be about 80 mm to about 110 mm long, preferably about 80 mm to about 100 mm long and about 7 mm to about 8 mm in diameter. For example, in an embodiment, the electronic smoking article is about 84 mm long and has a diameter of about 7.8 mm.

The outer cylindrical housing 22 of the electronic smoking article 60 may be formed of any suitable material or combination of materials. Preferably, the outer cylindrical housing 22 is formed of metal and is part of the electrical circuit.

Preferably, the liquid aerosol formulation for use in each of the electronic smoking articles 60 described herein includes at least one aerosol former, optionally water, and flavors. The liquid aerosol formulation can include nicotine or be nicotine free. Moreover, the liquid aerosol formulation can include tobacco flavors or other suitable flavors.

In the preferred embodiment, the at least one aerosol former is selected from the group consisting of propylene glycol, glycerin and combinations thereof. Preferably, the at least one aerosol former is included in an amount ranging from about 40% by weight based on the weight of the liquid formulation to about 90% by weight based on the weight of the liquid formulation (e.g., about 50% to about 80%, about 55% to about 75% or about 60% to about 70%).

Preferably, the liquid formulation also includes water. Water can be included in an amount ranging from about 5% by weight based on the weight of the liquid formulation to about 20% by weight based on the weight of the liquid formulation, more preferably in an amount ranging from about 10% by weight based on the weight of the liquid formulation to about 15% by weight based on the weight of the liquid formulation.

The liquid aerosol formulation optionally includes at least one flavorant in an amount ranging from about 0.2% to about 15% by weight (e.g., about 1% to about 12%, about 2% to about 10%, or about 5% to about 8%). The at least one flavorant can be a natural flavorant or an artificial flavorant. Preferably, the at least one flavorant is selected from the group consisting of tobacco flavor, menthol, wintergreen, peppermint, herb flavors, fruit flavors, nut flavors, liquor flavors, and combinations thereof.

When the word “about” is used in this specification in connection with a numerical value, it is intended that the associated numerical value include a tolerance of ±10% around the stated numerical value. Moreover, when reference is made to percentages in this specification, it is intended that those percentages are based on weight, i.e., weight percentages.

Moreover, when the words “generally” and “substantially” are used in connection with geometric shapes, it is intended that precision of the geometric shape is not required but that latitude for the shape is within the scope of the disclosure. When used with geometric terms, the words “generally” and “substantially” are intended to encompass not only features which meet the strict definitions but also features which fairly approximate the strict definitions.

It will now be apparent that a new, improved, and nonobvious electronic smoking article has been described in this specification with sufficient particularity as to be understood by one of ordinary skill in the art. Moreover, it will be apparent to those skilled in the art that numerous modifications, variations, substitutions, and equivalents exist for features of the electronic smoking article which do not materially depart from the spirit and scope of the invention. Accordingly, it is expressly intended that all such modifications, variations, substitutions, and equivalents which fall within the spirit and scope of the invention as defined by the appended claims shall be embraced by the appended claims. 

We claim:
 1. An electronic smoking article operable to produce an aerosol comprising: a liquid aerosol formulation; a heater operable to at least partially volatilize the liquid aerosol formulation and form an aerosol; and a filter segment formed of polylactic acid fibers or a crimped polylactic acid film, the filter segment including at least one additive and being positioned downstream of the heater and operable to elute the at least one additive into the aerosol as the aerosol passes through the filter segment.
 2. The electronic smoking article of claim 1, wherein the filter segment has a length ranging from about 2 mm to about 30 mm and an outer diameter that is about the same or less than an inner diameter of an outer housing of the electronic smoking article.
 3. The electronic smoking article of claim 1, wherein the polylactic acid fibers are substantially parallel.
 4. The electronic smoking article of claim 1, wherein the filter segment is detachable and a sleeve is operable to attach the filter segment to the electronic smoking article.
 5. The electronic smoking article of claim 1, further including a mouth end insert positioned downstream of the filter segment.
 6. The electronic smoking article of claim 1, further including a mouth end insert positioned upstream of the filter segment.
 7. The electronic smoking article of claim 1, wherein the at least one additive is selected from the group consisting of flavors, aerosol modifiers, aromatic materials, pH modifying agents, chemesthesis agents, volatile acids and combinations thereof.
 8. The electronic smoking article of claim 1, wherein the at least one additive is impregnated in the filter segment or included in a coating on at least one surface of the filter segment.
 9. The electronic smoking article of claim 1, wherein the at least one additive is encapsulated or microencapsulated.
 10. The electronic smoking article of claim 1, wherein the heater comprises a capillary in fluid communication with a reservoir.
 11. The electronic smoking article of claim 10, wherein the reservoir is pressurized and includes a mechanically or electrically operated valve at an outlet of the reservoir.
 12. The electronic smoking article of claim 10, wherein the reservoir is compressible such that the liquid material is manually pumped to the capillary.
 13. The electronic smoking article of claim 1, wherein the heater is a coil heater in communication with a filamentary wick which draws the liquid aerosol formulation from a reservoir via capillary action.
 14. The electronic smoking article of claim 13, wherein the electronic smoking article further comprises: an outer tube extending in the longitudinal direction; an inner tube within the outer tube; and the reservoir comprising the liquid aerosol formulation contained in an outer annulus between the outer tube and the inner tube, wherein the coil heater is located in the inner tube and the filamentary wick is in communication with the reservoir and surrounded by the coil heater such that the filamentary wick delivers the liquid aerosol formulation to the coil heater and the coil heater heats the liquid aerosol formulation to a temperature sufficient to vaporize the liquid aerosol formulation and form an aerosol.
 15. The electronic smoking article of claim 14, wherein the electronic smoking article comprises a first section attachable to a second section and wherein the filamentary wick, the reservoir and filter segment are contained in the first section and a power supply operable to apply voltage across the heater is contained in the second section.
 16. The electronic smoking article of claim 1, wherein the at least one additive is dispersed substantially uniformly throughout the filter segment.
 17. The electronic smoking article of claim 1, wherein a concentration of the at least one additive varies along a length of the filter segment.
 18. The electronic smoking article of claim 7, wherein the volatile acid is pyruvic acid.
 19. The electronic smoking article of claim 7, wherein the volatile acid is operable to reduce a pH of the aerosol to a pH ranging from about 4 to about
 8. 